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Cleaning circuit boards from old equipment - best method?

Discussion in 'General Electronics Chat' started by RogueRose, Nov 23, 2016.

  1. RogueRose

    Thread Starter Member

    Oct 10, 2014
    376
    10
    I do a lot of tear downs of old equipment and the cleanliness can range from almost factory fresh to looking like it lived its life in a vacuum bag (dust/dirt/insects/etc). The goal is to have the components as clean as possible for removal (of parts worth keeping). The boards range from PC power supplies, projection TV boards, UPS boards, stereo/amp boards, some motherboards & PC cards, etc - basically anything with interesting parts.

    I usually start with the air compressor and blow off dust/dirt/grim if needed but there is often stuff stuck on that doesn't come off. I've used something like windex or Fantastic sprayed on the boards (while dry), allow them to sit for 5-10 mins and then use a long bristle brush (like a toilet bowl scrubber but with softer & longer bristles) to lightly scrub the board & components followed by a spray of hot water to rinse everything off. After this they are stacked in front of a fan and air blown through them to dry as quickly as possible.

    I've never noticed any damage to any parts with this process but I'm not sure if something could be happening that I can't see. None of the ingredients in the sprays are particularly strong and shouldn't harm any components. I'm wondering if anyone has any insight into this or has a better approach to cleaning them. I've heard some people actually use a dish washer to clean some boards (I guess it depends on components). I've never noticed any rust on the steel heat sinks if there are any, even if there were traces of rust to begin with..

    Any thoughts on this?
     
  2. AlbertHall

    AAC Fanatic!

    Jun 4, 2014
    8,157
    2,023
    When I was doing this sort of stuff professionally we used something we called super soap - it was a concentrated detergent which we diluted. Brushed over the boards and then rinsed with plenty of water and dried.

    This resurrected an oscilloscope which had been on the bottom of Portsmouth harbour for a week.
     
    RogueRose likes this.
  3. ronv

    AAC Fanatic!

    Nov 12, 2008
    3,768
    2,862
    With the right detergent a dishwasher works pretty good.:)
     
  4. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    5,394
    1,194
    A "dishwasher" is basically what boards are sent through for cleaning post soldering to remove flux residue,etc.. Even with "no-clean" fluxes more than half of all PCB houses still do a cleaning process.. Mostly for the "visual" aspect anyways..
    Things like this.. http://www.speedlinetech.com/products/cleaners/aquastorm-100-in-line

    I use higher percent IPA (99% if possible) for all my board cleaning needs and a nylon,etc... bristle brush..
     
  5. RogueRose

    Thread Starter Member

    Oct 10, 2014
    376
    10
    This is good to know! I was told by a EE that there was a good possibility that I may damage some components but after I took many boards apart I found that most parts are pretty durable (except those made of glass and some porcelain).
     
  6. jlanders12

    New Member

    Nov 24, 2016
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